We do not use shared folders or shared calendars, which is
possibly what you are referring to. We us MAPI or ActiveSync to
allow access to email, calendar events, contacts and tasks on
multiple devices for the one user.

Funnily enough we were about to do a change where we had a large
shared calendar for our hotel back of office team (especially
reservations and functions). We have abandoned that idea for the
time being and I am now reassessing how we can best do it,
considering MAPI and Outlook 2016 currently are an unreliable
combination.

The most likely outcome at this stage is to move away from inhouse
mail server.

We had a Windows 10 PC with MSO2016. Outlook would not stop
crashing. We uninstalled and reinstalled MSO three times.
After the second time we tried installing MSO2013 instead. It
would not accept the product key. Yay.

The third time, we did not bother with MAPI. We gave it an
Active Sync account with the same CGP server and the problems
disappeared.

This will now be our answer for all Outlook 2016 crashing from
now on. I am no longer going to bother with MAPI. It is
causing too many problems for our sites. Sometimes is not good
enough.

About a third of our workstations have now experienced this
problem.

Please explain how providing your Outlook 2016/2013 users with
Active Sync allowed them to work in "workgroup" mode, with
Outlook.

Or.. are you asking them to use their smartphone or tablets to
manage contacts and calendars ?